Field of the Invention
This invention is directed to improvements relating to devices intended to create an optimum environment for the in vitro study of dynamic blood-material (biomaterial surfaces, biomedical devices and the like) interactions. Interactions commonly measured include changes in the character of blood and changes that take place within or on materials, surfaces, devices and the like following interaction with flowing blood. Such a device is shown in U.S. Pat. No. 3,766,774 which issued to Howard G. Clark on Oct. 23, 1973, the subject matter of which is incorporated herein by reference.
In addition to the aforementioned patent, the Clark device is described in an article entitled Controlled Flow Instruments for Simulating In Vivo Thrombosis; by H. G. Clark, B. A. Shinoda and R. G. Mason which appeared in Thrombos, Diathes, Haemorrh (Stuttg), 1973, 30, 519. It is also described in another article entitled Study of the Reactions of Blood With Artificial Surfaces-Use of the Thrombo Generator; by R. G. Mason, W. H. Zucker, B. A. Shinoda, H. Y. Chuang, H. S. Kingdon and H. G. Clark which appeared in volume 31, No. 2, at page 143 (1974), in the journal Laboratory Investigation. All of these articles are incorporated herein by reference also.
In the Clark apparatus, a continuous closed loop of tubing is filled with blood which is to undergo tests. The tubing is attached to the circumference of a balance wheel which is then oscillated about a fixed point. The inertia of the fluid in the oscillating tube causes the blood to tend to remain stationary about its location within the tube, leading to no net circulation of the blood within the tube. The oscillated closed loop thus creates some oscillatory shear-induced blood movement at the blood-wall interface and is thus intended to simulate pulsatile flow in the living circulatory system.